Charging a rechargeable external device by periodically powering down and powering up portions of the charging device until the rechargeable external device is recharged

ABSTRACT

A system which enables battery powered devices such as notebook computers to efficiently charge smaller mobile devices such as music players, cell phones and PDAs using the power signals provided over their data connections is made more efficient by ensuring that the power to the small mobile device is not interrupted should the notebook computer otherwise go into a standby or low-power state. The presence of the small mobile device is known and any power-down capabilities of the notebook computer are limited, at least for the period where the small mobile device is being recharged. This detection can be done at any of the levels of software present in the notebook computer. This charging and not powering down can be further optimized by determining the particular device and its charging requirements or by having the device provide feedback as to its charge state.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.11/216,321 filed Aug. 31, 2005, which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to electronic devices used to charge andcommunicate with mobile electronic devices.

2. Description of the Related Art

In modern society we are becoming ever more mobile. It is very common tohave notebook computers in small and light form factors to greatly aidin communications and computing in varying locations. One common aspectof notebook computers is that they are battery powered. As a result,they all have some sort of algorithm to conserve the battery power.Typically this includes entering low-power or standby states afterdetermined periods of inactivity. During these standby or low-powerstates one of the common things that is done is to turn off power to allof the peripheral devices and peripheral ports.

Also common in the modern mobile society are small electronic mobiledevices such as cell phones, music players and PDAs (Personal DataAssistants). All of these are very small, battery powered personaldevices. In many cases they connect to a larger computer, such as anotebook computer or a desktop computer, to receive files and tootherwise interface with the larger computer system. Because they aresmaller devices and battery powered, they have a limited lifetime ontheir battery charge. To this end they need to be charged on areasonably frequent basis.

One of the common ways that has been developed for these types ofdevices to be recharged is to plug them into the computer using theirdata connection and then use the power provided on that data connectionto recharge the devices. For example, say the device connects by a USBor 1394 interface. A constant DC voltage is provided on each of thoseinterfaces and this DC voltage can be readily used to recharge thebatteries in the mobile device. In this manner the user does not have tocarry around AC adapters for each of the particular devices and does nothave to rely on disposable batteries. They can just use their standarddata connection cable for recharging capabilities. This recharging ofthese small mobile devices is not an appreciable draw or drain on thenotebook computer battery, for example, as that is a very high capacitybattery as compared to the particular small devices.

Given that this capability of charging the small mobile devices from thelarger mobile device such as the notebook computer is common andbecoming ubiquitous, it is desirable to be able to make this process asefficient as possible to simplify user operations.

BRIEF SUMMARY OF THE INVENTION

A system according to the present invention enables battery powereddevices such as notebook computers to efficiently charge smaller mobiledevices such as music players, cell phones and PDAs using the powersignals provided over their data connections. This is done efficientlyby ensuring that the power to the small mobile device is notinterrupted, particularly not interrupted should the notebook computerotherwise go into a standby or low-power state. This addresses a problemwhich has been determined in existing devices where, when the notebookcomputer goes to sleep or powers down, all the peripheral device portsare turned off and power is disconnected from them. Thus this powerdisconnection removes the power connection being used simply to chargethe small mobile devices.

In systems according to the present invention, the presence of the smallmobile device is known and any power-down capabilities of the notebookcomputer are limited, at least for the period where the small mobiledevice is being recharged. This detection can be done at any of thelevels of software present in the notebook computer. For example, anapplication can detect the presence of the device and then tell theoperating system not to go into a low power state. The detection can bedone by the operating system itself and thus detect that it should notitself go into the low-power state. It can be done at a lower firmwarelevel so that even should the operating system try to put the computerinto a power-down state, the firmware or BIOS will override suchcapabilities.

This charging and not powering down can be further optimized bydetermining the particular device and its charging characteristic orcharging requirements or by having the device provide feedback as to itscharge state. As soon as it is determined that the device is fullycharged, then the notebook computer can be returned to full power-downconditions as in normal operations.

Thus by not allowing the computer to power-down at least the powerprovided through the peripheral data ports, the small mobile devices canbe rapidly charged.

A BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a drawing illustrating various small mobile devices connectedto a notebook computer.

FIG. 2 is a block diagram of an exemplary notebook computer includingthe details relating to the power connections for the peripheral deviceports.

FIG. 3 is a block diagram illustrating the various software layerspresent in an exemplary notebook computer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, an exemplary notebook computer 100 is connectedto a music player 102 and a PDA 104. The music player 102 is connectedto the notebook computer 100 using a link 106 such as USB or 1394.Similarly, the PDA 104 is connected to the notebook computer 100 using adata link 108, again a USB link in common practice or a 1394 or otherlink as desired. The data links 106 and 108 are the conventional datalinks used between the devices 102 and 104 and the notebook computer 100to transfer data. For example, the data link 106 is normally used totransfer music files between the notebook computer 100 and the musicplayer 102. The data link 108 is used to provide the communicationsbetween the notebook computer 100 and the PDA 104. By using the powerlines present on the data links, it is thus possible to charge thevarious mobile devices, such as the music player 102 or the PDA 104.

Referring now to FIG. 2, a simplified block diagram of the exemplarynotebook computer 100 is shown. A power supply 200 is used to power thenotebook computer 100 and any devices connected to the notebook computer100 as desired. Most of the power supply connections are not shown forsimplicity. A processor or CPU 202 forms the core processing element ofthe notebook computer 100. The processor 202 is connected to a bridgechip 204 which connects the processor 202 to memory (not shown) and tovarious peripheral buses as desired. One of the peripheral busesprovided by the bridge 204 can be a bus such as a PCI bus 206. In theillustrated example a USB host controller 208 is connected to the PCIbus 206, as is a 1394 host controller 210. The USB host controller 208is connected to a USB connector 212. It can be seen that the two datalines 214 in the USB connection are provided directly from the USB hostcontroller 208 to the USB connector 212. One of the other connections onthe USB connector 212 is connected to ground. Similarly the 1394 hostcontroller 210 provides four data lines 216 to a 1394 connector 218. Afifth line on the illustrated 1394 connector 218 is connected to ground.The final line on each of the USB connector 212 and the 1394 connector218 is a power line.

To assist and manage the power-down of the notebook computer 100 a powermanagement unit 220 is connected to the processor 202, to the bridge 204and to the power supply 200. The power management unit 220 has variousrequirements and capabilities to detect system operation and to alsotimely control the power down of the various systems in the notebookcomputer 100. This includes control of clock systems (not shown) andvarious transistors used to control switchable power lines. For example,power management unit 220 is connected to the gate of a transistor 222.The drain of the transistor 222 is connected to the power supply 200while the source of the transistor 222 is connected to the power pin ofthe 1394 connector 218.

In a similar manner the USB host controller 208 is connected to the gateof a transistor 224, whose drain is connected to the power supply 200and whose source is connected to the power pin of the USB connector 212.Thus the power management unit 220 is responsible for controlling thetransistor 222 to provide power to the 1394 connector 218, while the USBhost controller 208 includes internal registers to control thetransistor 224 which provides power to the USB connector 212. There isalso a link between the power management unit 220 and the bridge 204 toallow the processor 202 to interoperate and communicate with the powermanagement unit 220.

Therefore if power-down of the notebook computer 100 is desired, thepower management unit 220 disables or turns off the transistor 222 whilethe USB host controller 208 is instructed by the processor 202 to turnoff or disable the transistor 224. The power management unit 220 in manycases also controls power to the USB host controller 208 and the 1394host controller 210 such that they are powered-off, as well as havingtheir clock signals stopped.

Referring now to FIG. 3 a simple diagram of the software present in theexemplary notebook computer 100 is shown. The lowest level of softwareis the BIOS or basis input/output system 300. This is the lowest levelof software and is often contained in an EPROM and is otherwise known asfirmware. The BIOS 300 provides the lowest level of interconnect betweenthe physical devices, i.e., the peripheral devices, and the higher levelsoftware in the notebook computer 100. Interacting with the BIOS 300 arethe drivers 302. These drivers act as an interface between the low-levelfunctionality of the BIOS 300 and the high-level operations of theoperating system 304. Present above the operating system 304 are theindividual applications 306.

As noted above, it has been determined that one of the problems with asystem as shown in FIG. 1 is that should the notebook computer 100 gointo a power-down or sleep mode, power on the exemplary 1394 and USBconnectors 212 and 218 is disabled. Thus any charging of the connectedmusic player 102 or PDA 104 is halted while the laptop or notebookcomputer 100 is in the low power state.

In systems according to the present invention, one of the softwaremodules, such as the BIOS 300, the operating system 304, the drivers 302or the applications 306, determines the existence and connection of anexternal device such as the music player 102 or the PDA 104. In oneembodiment the appropriate recognizing software can then instruct theoperating system 304 not to disable the power to the connected mobiledevice. This can be done in several manners. For example, if it is anapplication program, such as iTunes from Apple Computer, Inc., theapplication can detect an attached iPod from Apple Computer, Inc., andinform the operating system at a high level not to perform any powermanagement functions. This state can remain in effect even if theapplication is terminated.

While this approach is quite satisfactory at performing the desiredfunction of recharging the mobile device, there are further optimizedembodiments. For example, the operating system 304 can also detect thepresence of the connected mobile device. The operating system 304 canthen on its own not enter the power-down state. Alternatively, theoperating system 304 can enter a power-down state for all componentsexcept for the particular port to which the mobile device is connected.In a further embodiment, the data connections to that particularconnected port can be powered down, just so long as the powerconnection, i.e., the DC connection from the appropriate transistor 222or 224, is still being provided to charge the device. This could alsoadditionally be done at the driver level or BIOS level if desired.

In the most simplistic embodiments, the port or the computer is notpowered down until it is detected that the device has been removed. Thismay be inefficient in certain cases, such as the mobile device beingfully charged and yet the notebook computer 100 will still not beallowed to go into a lower-power state, but it is still an improvedmanner of charging the mobile device. This embodiment can be optimizedby determining the particular type of peripheral or mobile deviceattached to the notebook computer 100 and determining its power chargingcharacteristics. For example, in certain instances the mobile device isrelative simplistic and its recharging time is known. Therefore thecontrolling function, such as the application software, can inform theoperating system not to go into the low-power state for a time greaterthan the known recharging time of the mobile device.

In a more sophisticated example, the mobile device can report itscharging status and therefore the relevant software can periodicallyquery the mobile device and determine its charge state. When the deviceis fully charged, then the application or other software can instructthe operating system that full power-down can occur.

Another enhancement is a determination whether the charging device suchas the notebook computer 100 is operating on AC power or is itselfoperating on DC power. Should the operation be on AC power, then arelatively simplistic operation can be used such as not entering anypower-down state. If, however, it is operating in a DC power conditionoff its own internal battery, then more sophisticated algorithms, suchas feedback of actual charge status or defined time as discussed above,can be utilized if desired. Further, the notebook computer 100 canactually go into a lower-power state periodically while still havingpower to the attached mobile device being provided. The notebookcomputer 100 can then wake-up periodically to query the attached mobiledevice to determine if it has been fully charged. If it has not beenfully charged, the cycle can repeat as the notebook computer 100 goesinto another power-down state until the next time to wake-up and checkcharging status. When the mobile device finally indicates a fullycharged state, even the power to the mobile device can be disabled andthe notebook computer 100 can stop the periodic wake up.

While a notebook computer 100 has been used as an example host device toprovide the charging capabilities, it is understood that desktopcomputers and numerous other types of electronic devices which alsoenter power-down states and which can be used to recharge smaller mobiledevices can perform in a similar manner. For example, if a televisionset were to have the appropriate 1394 port, it could be used to charge a1394 connected device, such as a music player. The television set coulddetermine that it is being used as a charging source for the musicdevice and not turn off that port. While 1394 and USB connections havebeen used as examples, it is understood that any connection providingpower, such as PS/2 keyboard and mouse connections, may be utilized.Further, it is understood that the operations can be performed inparallel for multiple connected devices.

The preceding description was presented to enable any person skilled inthe art to make and use the invention as claimed and is provided in thecontext of the particular examples discussed above, variations of whichwill be readily apparent to those skilled in the art. Accordingly, theclaims appended hereto are not intended to be limited by the disclosedembodiments, but are to be accorded their widest scope consistent withthe principles and features disclosed herein.

1. A device comprising: a power supply; a port coupled to said powersupply to provide power connections from said port, said port forconnecting an external rechargeable device; and a power managementelement coupled to said power supply and said port for controllingnormal powering down of the device; wherein said power managementelement determines the connection of a rechargeable external device tothe port and limits the powering down of the device so that therechargeable external device continues to receive power from said port,wherein limiting the powering down includes: allowing selected portionsof the device other than said port to be powered down; periodicallypowering up selected portions of the device to determine if therechargeable external device is recharged; if the rechargeable externaldevice is not recharged, powering down said portions of the device thatwere powered up; and if the rechargeable external device is recharged,no longer limiting powering down of the device.
 2. The device of claim1, wherein said power supply includes a battery and the device isconfigured to be powered from an AC source or said battery, and whereinlimiting the powering down is performed differently if the device ispowered from the AC source or said battery.